1. Field of the Invention
This invention pertains to pumps, compressors and the like. More specifically, this invention pertains to such pumps and/or compressors which utilize movable vanes which are slidably located within slots in a rotating rotor and which move up and down within the rotor in response to the curvature of an enclosing, circumferential cylinder wall.
2. Description of Prior Art
Many pumps and compressors are known which utilize movable vanes. In these devices, the vanes are forced outwardly by centripetal acceleration resulting from the rotation of a central rotor. These vanes move outwardly until they touch a cylinder wall. Because the wall is of a non-circular shape, the vanes are forced inwardly when the wall approaches the rotor and can move outwardly when the wall moves away from the rotor. In these devices, it is necessary to provide a small amount of clearance between the vane and the rotor in order to allow the vane to slide inwardly and outwardly. Because of the pressures resulting from the fluids which are compressed and/or pumped, the vanes, when in actual use, do not actually lie parallel to the walls of the slots in which they move. Rather, these vanes are forced rearwardly so that their trailing faces abut the trailing surfaces of the slots. As a result of this inclination of the vanes with respect to the slots, the trailing edge of each slot is forced against the trailing face of the corresponding vane.
This phenomenon results in friction, and consequently results in substantial abrasion of either the vane or the rotor. After such abrasion has continued, the play between the vane and the rotor becomes too great, and the pump or compressor must be disassembled and serviced.
Conventionally, this problem has been attacked by using greases and oils on the faces of the vane and/or the surfaces of the rotor. Although this lubrication has been somewhat successful, the underlying problem, namely frictional contact between the trailing edge of the rotor and the trailing face of the vane, still exists and still remains desirable.